The most important subject in studies for improving the efficiency and characteristic of a semiconductor device is to reduce the crystal defect of a semiconductor layer grown on a substrate and to improve crystallinity of the semiconductor layer.
However, a base substrate comprising silicon carbide may have various defects, such as a defect created in a basal plane of a lattice, a defect caused by the tilting of the lattice, and a defect created on a surface of the base substrate. These defects may exert bad influence upon the semiconductor device when an epitaxial layer is grown. In addition, these defects may exert bad influence upon the operation of a switching device.
In particular, the base substrate comprising silicon carbide may have the basal plane dislocation (BPD). Since the BPD exerts great influence upon the reliability of the semiconductor device, it is very important to reduce the BPD.
According to the related art, a buffer layer is formed in order to reduce the BPD during the crystal growth process. Thus, a mask forming process, a pattern forming process through etching, and a regrowing process are additionally necessary to form the buffer layer.
Due to the above additional processes, the manufacturing process is complicated, the manufacturing cost is increased, and the quality of a substrate surface is deteriorated.
Accordingly, there is necessary to provide a semiconductor device capable of controlling the BPD of the base substrate without forming the buffer layer and a method for growing a semiconductor crystal.